Inflatable shaft

ABSTRACT

An inflatable shaft mainly includes an elastic rubbery sleeve mounted around the outer wall of plural outer pressing boards and able to expand outward to cover gaps formed among the outer pressing boards while inflating the inflatable shaft, so as to provide a seamless exterior surface for the air expanding shaft to be directly wound with a stuff without having the stuff sunk or clamped. And, the rubbery sleeve can shrink inward together with the outer pressing boards while deflating the inflatable shaft, forming a space between the rubbery sleeve and the stuff to enable the stuff easily separated from the deflated shaft. Thus, the stuff can be smoothly wound around the inflatable shaft inflated without using an additional tube, not only lowering manufacturing cost but also amiable to environment.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an inflatable shaft, particularly to one ableto keep a stuff directly wound around after the inflatable shaft isinflated and easily separated from the wound stuff after deflated,needing to use no additional shaft, not only lowering manufacturing costbut also amiable to environment.

2. Description of the Prior Art

Commonly, a stuff (A), such as shrinking film, packaging film or windingfilm etc., is wound around a tube 10 inserted with a conventionalinflatable shaft 1. The tube 10 is made of paper or plastics etc. Withthe inflatable shaft 1 installed and inflated on a winding device, thetube 10 can be driven to rotate to wind up the stuff (A). As shown inFIGS. 1 and 2, the conventional inflatable shaft 1 is provided with atubular main body 11, an air bag 12 installed inside the main body 11, aplurality of inner pressing boards 13 attached to the outer wall of theair bag 12, a space 14 formed between the pressing boards 13 and themain body 11, a plurality of outer pressing boards 15 attached to theouter wall of the main body 11, and a plurality of connecting bars 16penetrated through the main body 11 to connect the inner pressing boards13 with the outer pressing boards 15. In using, the inflatable shaft 1is inserted in the tube 10 and the air bag 12 is inflated to expandoutward. By the time, the inner pressing boards 13 are squeezed to moveoutward to approach the main body 11 so as to push outward the outerpressing boards 15 moving away from the outer wall of the main body 11to approach the inner wall of the tube 10. So, the tube 10 is closelyattached by the inflatable shaft 1 inflated, able to be driven by theinflated shaft 1 to rotate so as to make the stuff (A) wound around it.However, the tube 10 is to be dumped after the stuff (A) is used up,posing waste of source and ecological contamination. If the stuff (A) isto be directly wound around the air expanding shaft I instead of thetube 10 for environmental amiability, it is to sink into gaps (B) (asshown in FIG. 3) created between every two adjacent outer pressingboards 15 while inflating the inflatable shaft 1, formed with anunsmooth surface. When the inflated shaft 1 is deflated, the stuff (A)sinking in the gaps (B) is to be clamped by the outer pressing boards 15because of shrinkage of the gaps (B), keeping the stuff (A) uneasy to beseparated from the deflated shaft 1. It is obvious that the process ofdirectly winding the stuff (A) around the inflatable shaft 1 isabsolutely not good.

SUMMARY OF THE INVENTION

The object of this invention is to offer an inflatable shaft able tokeep a stuff directly wound around with the inflatable shaft inflatedand easily separated from it with the inflated shaft deflated, notneeding to use an additional shaft, not only lowering manufacturing costbut also amiable to environment.

The inflatable shaft of the invention is characteristically providedwith a rubbery sleeve mounted around the outer wall of its outerpressing boards.

BRIEF DESCRIPTION OF DRAWINGS

This invention is better understood by referring to the accompanyingdrawings, wherein:

FIG. 1 is cross-sectional view of a conventional inflatable shaft;

FIG. 2 is cross-sectional view of the conventional inflatable shaft,showing it being inserted in a tube that is wound with a stuff afterhaving the inflatable shaft inflated;

FIG. 3 is cross-sectional view of the conventional inflatable shaft,showing it inflated and directly wound with the stuff;

FIG. 4 is an exploded perspective view of a preferred embodiment of aninflatable shaft in the present invention;

FIG. 5 is a perspective view of the preferred embodiment of aninflatable shaft in the present invention;

FIG. 6 is a cross-sectional view of the preferred embodiment of aninflatable shaft in the present invention, showing it not inflated yet;

FIG. 7 is a cross-sectional view of the preferred embodiment of aninflatable shaft in the present invention, showing it wound with thestuff after inflated; and

FIG. 8 is a cross-sectional view of the preferred embodiment of aninflatable shaft in the present invention, showing it deflated afterwound with the stuff.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in FIGS. 4˜6, a preferred embodiment of an air expanding shaft2 in the present invention is provided with a tubular main body 20, anair bag 21 installed inside the main body 20, a plurality of innerpressing boards 22 attached to the outer wall of the air bag 21, a space23 formed between the pressing boards 22 and the main body 20, aplurality of outer pressing boards 24 attached to the outer wall of themain body 20, a plurality of connecting bars 25 penetrated through themain body 20 to connect the inner pressing boards 22 with the outerpressing boards 24, and a rubbery sleeve 26 mounted around the outerpressing boards 24.

In using, as shown in FIG. 7, when a stuff (A) is to be wound around theinflatable shaft 2, the air bag 21 must be first inflated to expandoutward so as to also push outward the inner pressing boards 22, whichare to successively approach the main body 20 and push outward the outerpressing boards 24 by means of the connecting bars 25. By the time, theouter pressing boards 24 are to be separated from the outer wall of themain body 20 to enable the rubbery sleeve 26 squeezed to expand outward.The stuff (A) can thus be wound around the inflatable shaft 2 inflated.Next, as shown in FIG. 8, while the stuff (A) is to be separated fromthe inflated shaft 2 after wound with a desired thickness, the air bag21 of the inflated haft 2 is deflated first to shrink inward. The innerpressing boards 22 resting on the air bag 21 are simultaneously movedinward to keep the space 23 between the inner pressing boards 22 and themain body 20 widened. And, by means of the connecting bars 25, the outerpressing boards 24 are to be also forced to move inward to attach to theouter wall of the main body 20 again, so that the rubbery sleeve 26 isto shrink inward to create a space (C) between itself and the stuff (A).Therefore, the stuff (A) well wound without an additional tube can beeasily separated from the deflated shaft 2.

It is to be noted that, with the rubbery sleeve 26 mounted around theouter pressing boards 24 to expand outward while inflating the air bag,the gaps (B) formed among the outer pressing boards 24 are covered bythe rubbery sleeve 26 that can be wound with the stuff (A) smoothlywithout having the stuff (A) sunk into the gaps (B) and clamped by theouter pressing boards 24 as happening in the conventional inflatableshaft. And, as the rubbery sleeve 26 can follow the outer pressingboards 24 to shrink inward while deflating the air bag 21, the space (C)is to be formed between the rubbery sleeve 26 and the wound stuff (A) toenable the stuff (A) easily separated from the deflated shaft 2.Therefore, by means of the inflatable shaft 2 of the invention, thestuff (A) can be smoothly wound without using an additional tube, notonly lowering manufacturing cost but also amiable to environment.

While the preferred embodiment of the invention has been describedabove, it will be recognized and understood that various modificationsmay be made therein and the appended claims are intended to cover allsuch modifications that may fall within the spirit and scope of theinvention.

1. An inflatable shaft comprising a tubular main body, an air baginstalled inside said main body, a plurality of inner pressing boardsattached to an outer wall of said air bag, a space formed between saidinner pressing boards and said main body, a plurality of outer pressingboards attached to an outer wall of said main body, a plurality ofconnecting bars penetrated through said main body to connect said innerpressing boards with said outer pressing boards; and said inflatableshaft characterized by having a rubbery sleeve mounted around said outerpressing boards.